Insulating material



July 4, 1950 R. F. WALTER Er AL 2,514,170

INSULATING MATERIAL 2 SheetsqSheet 1 Filed Oct. 12, 1945 July 4, 1950 R.F. WALTER n AL 2,514,170

INSULATING MATERIAL Filed oct. 12, 1945 2 sheets-sheet z Patented July4, 1950 INSULATING MATERIAL Robison F. Walter, Manheim, and William J.

Joyce, Jr., Lancaste bestos-Manhattan, ration of New Jersey r, Pa.,assignors to Ray- Inc., Passaic, N.

J., a corpo- Application October 12, 1945, Serial No. 621,002

g 3 Claims.

This invention relates to high temperature insulating material of novelconstruction.

It is an object of the present invention to provide a flexible,resilient insulating composite adapted to be Wrapped about the surfacesof conduits and the like tubular conductors or containers of hightemperature vapors and gases, for the primary purpose of protectingpersonnel from being burned by contact with highly heated surfaces,rather than for the purpose of conserving heat, although not so limited.

More particularly, it is an object of the present invention to providean insulating wrapper' or envelope adapted to withstand temperatures onthe order of 1000 F., or more suitable for use as a covering for highpressure steam pipes, exhaust manifolds of Diesel engines, parts of jetpropulsion airplane engines, gas turbines, and other engines or machinesoperating at very high temperatures.

Further objects relate to the production of a high temperatureinsulating composite or envelope adapted to withstand long periods ofuse, which may quickly and conveniently be applied to the desiredsurface or part of an engine or machine, which may be removed withoutdamage to itself if the engine or machine requires repairs or is to bedisassembled and which may be again replaced to continue its usefulfunctions after repair or reassembly is completed.

In general our high temperature insulating material comprises anenvelope having a. base or heated object contact surface or section ofmetallic fabric constructed and arranged to permit air currents todissipate a portion of heat by convection (and a certain amount to bealso lost by radiation) before it can do harm to the heat resistantmaterials just about it, While being able to withstand high temperaturesand remain flexible; an upper or outer surface of woven generallyconventional heat resistant fabric; and a ller or intermediate bodysection, preferably including loosely packed heat resistant bresconstructed and arranged so that the transfer of heat from the source ofheat to the outer or top layer is reduced to a minimum.

Further objects and advantages of our insulating material, and itsdetails of construction, modilications, and arrangement of parts will beapparent from a consideration of the following specification anddrawings, wherein:

Fig. 1 is a perspective view of a high temperature heat insulating unitin accordance with our invention. y

Fig. 2 is an enlarged diagrammatic section on the line 2-2 of Fig. l.

Fig. 3 is e, perspective view illustrating the employment of theinsulating unit of Fig. 1.

Fig. 4 is an enlarged diagrammatic section similar to that of Fig. 2,but illustrating a modified form of construction.

Fig. 5 is another view similar to that of Fig. 2 illustrating a furthermodied form of construction.

Fig. 6 is a similar view illustrating another modication of ourconstruction.

Referring to the drawings, the reference numeral I0 generally indicatesa flexible and resilient high temperature heat insulating and shieldingcomposite blanket adapted to be used as a covering for highly heatedsurfaces or conduits such as, for example, the tubular conduit orexhaust pipe II, or components of other engines or machines previouslydescribed, for the prime purpose of providing a heat shield. In orderthat this insulating composite or blanket may be easily applied to anengine or machine and so that it may be removed without damage to itselfif the engine or machine requires repairs or is to be disassembled, theend portions of the outer surface of the composite may be provided withhooks i2 whereby the composite may be suitably and securely held againstthe surface to be insulated by means oi laces I3, or the like fasteningor securing means.

Referring more particularly to Fig. 2, this form of our insulatingcomposite comprises an envelope formed of an outer covering layer I4 ofwoven heat resistant fibrous material such as a cloth of woven fibrousasbestos, woven brous glass, Woven composites of glass and asbestosfibers, or the like, and a base layer I5 of very open mesh iiexiblemetallic fabric. The outer covering layer I 4 is of lesser area than thebase layer I5 and the two are joined together, as by stitching at theirdeiining edges as at I6, so as to form an envelope. More particularly,the flexible metallic fabric layer I5 is provided with upturned edges asat Il to form side walls, the edges of these side walls being joined tothe edges of the cloth covering layer I4, as previously indicated, atI6.

The base layer I5 is preferably composed of one or more plies of knittedwire, and suitably a two-ply layer may be employed resulting from thecollapsing of conventionally produced tubularlknitted metallic meshfabric. The knitted wire used maybe made from different metals ormetallic alloys and is preferably made of finely drawn, tough wiresknitted with relatively coarse loops having relatively large openings.For example, this material may be made from ordinary steel wire for usewhere corrosion is not a factor or from alloys which are non-corrosive,or from lighter metals and alloys where weight control is essential.

As indicated, this layer of flexible metallic fabric is of a very openmesh and is further formed with crimps or corrugatlons. The crimpingpattern used for distorting the material of layer I5 may be any one of alarge number of patterns, but preferablyl a corrugated formation isemployed which will produce a layer having greatest resistance toflattening after crimping with the minimum amount of contact with theheat source. The crimps are formed to provide a number of uniformly wideand deep furrows across the entire base of the composite, and preferablyalso extending along the sides I1, the crimps or corrugations being, forexample, of y; inch depth.

Immediately above and in direct contact with the crimped base layer I5,there is placed one or more thicknesses of relatively at open meshflexible metallic fabric I8 having relatively smaller meshes. closerknitted metallic or wire cloth I8, the number of effective furrows ofthe base layer I5 is doubled and the tendency of any iiuiy fibrousfiller material I9, to fall through and lill the furrows made bycorrugation of the base layer I5 is reduced to a minimum.

The envelope or pocket is filled with loosely packed heat resistantfibrous material, such as asbestos, glass wool, mineral wool, slag wool,flberglas, or the likeV non-combustible fibrous material. Y

The employment of a metallic base fabric enables the formation of ablanket which remains flexible under all conditions of temperature andone which can withstand high temperatures. The crimped formation of themetallic base provides furrows through which air currents may circulateand dissipate some of the heat by convection before it can damage thefiuiy insulating material I9, and removes the filler material from tooclose proximity with the heat source. The crimps or corrugations alsooffer more heat protection to the fibrous filling I9 from radiated. heatby locating the fibrous stock further away from the heat source. Inaddition, the corrugations provide point contact between the insulationand the heat source instead of surface contact thus reducing thetransfer of heat by conduction. The layer of exible metallic fabric I8placed over the base layer I5 doubles the number of furrows in the baselayer thus increasing the circulation of air currents between the heatsource and the insulation ller I9, and also acts as a protecting mediumto prevent the uiy filler material I9 from falling out of the envelopeor through the very open meshes of fabric I5.

The fiuiy, fibrous, heat resistant filling material I 9 provides aexible highly porous layer between the inner and outer layers, or topand bottom of the blanket, so that the transfer of heat from the sourceof heat to the outer or top layer I4 is reduced to a minimum.

The outer layer I4 of woven heat resistant fibrous cloth provides a heatand fire resistant covering and remains flexible and strong during along period of use.

Operating tests conducted on a heat insulating composite made inaccordance with the form of Fig. 2, and having a thickness of one inch,showed that it was 'able to withstand a temperature of l000 F., for aperiod of 600 hours. During such use the temperature on the outsideaveraged By the addition of this relatively about 200 F. During thisA60!) hour period of use, the temperature on the hot side rose atintervals to 1400 F. At the end of this test period, the insulatingcomposite was still in excellent condition and as far as could beobserved, could be replaced and continued in service indefinitely.

Thus, in general,v it will be seen that by employing a construction suchas hereinbefore described and illustrated, including brous insulatingmaterials, which would ordinarily be destroyed by direct contact withthe high heat of the hot elements to be insulated and shielded, thebrous material 1s protected and its life prolonged by being positionedand removed out of contact with the direct heat source, by interpositionof a metallic base fabric of crimped or corrugated form providing airspaces between the hot body and the fibrous insulating material.Although this construction takes full advantage of the fact that the airspaces resulting from the employment of' the corrugated base fabric I5,do act as an insulation aid, their formation is incidental to and theresult of the maintaining of the less heat resisting insulation fillermaterials I9 as far away from the source of heat as possible, so as toprevent their destruction by direct contact with the hot elements, andthus prolonging the life of usefulness of the composite, and theprevention of rapid transfer of heat from the heat source to the outersurface of the covering fabric I4.

'Ihe constructionV of modied form of Figs. 4 and 5 are particularly welladapted for use on gas turbines and jet propulsion engines where evenhigher temperatures, such as from 1300 F., to 1700 F., are encountered.

As shown in Fig. 4 the insulating composite may be constructed withmultiple layers of corrugated metallic mesh fabric instead of the singlelayer of Fig. 2, and the several layers of metallic mesh fabric employedmay be made from different metals or metallic alloys. 'I'hese materialsmay be laid in layers, each one of which is madel from the samematerial, or they may be laid in such a way that the layer next to thesource of heat shall have the highest heat resistance with thesubsequent layers having less and less heat resistance, and thematerials from which the metallic fabric is made may be entirelydifferent in each layer. One or more of the layers may be composed ofsemi-metallic fabric, such as a composite of metallic and asbestosstrands or filaments.

Thus in the construction of Fig. 4, the composite is essentially that ofFig. 2 with the addition of a second layer of corrugated open meshmetallic fabric 20 over the fiat layer I8, and another layer of atmetallic mesh fabric 2| may be positioned upon the corrugated layer 2Q.It will be understood that if desired additional and alternating layersof corrugated and flat metallic mesh fabric may also be employed.

With this multiple corrugated metallic mesh fabric layer construction,it is possible to reduce the thickness of fibrous heat resistant fillermaterial I9 required to complete the insulation, and to remove thefiller I9 still further from the heat source. In this form ofconstruction, the uppermost layer of uncrimped or fiat metallic meshfabric 2I may or may not be employed.

Fig. 5 shows another modified construction in which a metal heatreflecting foil 22, having a thickness of about .002 to about-.004 inch,is interposed between the woven cloth cover I4 and the metallic meshfabric arrangement of Fig. 4,

and in place of the filler material I9 thereof.

With this form of construction the foil 22 may be used in conjunctionwith a layer of heat resistant fibrous filling material, I9' as shownbest in Fig. 6, and such composite construction is preferred.

It will be further understood that in installations of our insulatingblanket, where the absorption of oil or water by the cloth cover I4and/or by the fibrous filling material I9 may be consideredobjectionable, such objections may be corrected by coating the covercloth Il with suitable synthetic resins or synthetic rubber compoundswhich are unaffected by oil and water, and the fibrous filling materialmay likewise be treated with a material which will render it imperviousto oil or water.

We claim as our invention:

l. A flexible and resilient high temperature heat shielding compositeblanket comprising an outer covering layer of woven heat resistantfibrous material, an outer base layer of open mesh corrugated flexiblemetallic fabric the corrugations of which are self-supported, anintermediate layer of loose heat resistant fibrous material, and aninterposed layer of open mesh flexible metallic fabric being of smallermesh than said corrugated fabric and supporting said loose fibrousmaterial above the ridges of said corrugated base layer, said basefabric having upturned edge portions forming side walls extendingsubstantially the thickness of the blanket joined edgewise to said outercovering layer and forming an envelope therewith.

2. A exible and resilient high temperature heat shielding compositeblanket comprising an outer covering layer of woven heat resistantfibrous material, an outer base layer of open mesh corrugated flexiblemetallic fabric the corrugations of which are self-supported, anintermediate layer of loose heat resistant fibrous material. and aninterposed layer of open mesh flexible metallic fabric being of smallermesh than said corrugated fabric and supporting said loose fibrousmaterial above the ridges of said corrugated base layer.

3. A flexible and resilient high temperature heat shielding compositeblanket comprising an outer covering layer of woven heat resistantfibrous material, an outer base layer of open mesh corrugated flexiblemetallic fabric the corrugations of which are self-supported, anintermediate layer of loose heat resistant fibrous material, aninterposed layer of open mesh flexible metallic fabric being of smallermesh than said corrugated fabric and supporting said loose fibrousmaterial above the ridges of said corrugated base layer, and meanscomprising edge portions forming side walls extending substantially thethickness of the blanket joined edgewise to said outer covering layerand forming an envelope therewith.

ROBISON F. WALTER. WILLIAM J. JOYCE, Ja.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 389,542 Bradley Sept. 18, 1888570,634 Hicks Nov. 3, 1896 1,209,315 OMalley Dec. 19, 1916 1,742,775Malley Jan. 7, 1930 1,827,035 Mottweiler et al. Oct. 13, 1931 1,984,190Hufllne- Dec. 11, 1934 2,170,207 Mosier et al Aug. 22, 1939 2,175,948Adams Oct. 10, 1939 2,264,961 Ward Dec. 2, 1941 2,330,941 Acuff Oct. 5,1943 2,358,550 Williams Sept. 19, 1944 2,425,293 McDermott Aug. 12, 1947

1. A FLEXIBLE AND RESILIENT HIGH TEMPERATURE HEAT SHIELDING COMPOSITEBLANKET COMPRISING AN OUTER COVERING LAYER OF WOVEN HEAT RESISTANTFIBROUS MATERIAL, AN OUTER BASE LAYER OF OPEN MESH CORRUGATED FLEXIBLEMETALLIC FABRIC THE CORRUGATIONS OF WHICH ARE SELF-SUPPORTED, ANINTERMEDIATE LAYER OF LOOSE HEAT RESISTANT FIBROUS MATERIAL, AND ANINTERPOSED LAYER OF OPEN MESH FLEXIBLE METALLIC FABRIC BEING OF SMALLERMESH THAN SAID CORRUGATED FABRIC AND SUPPORTING SAID LOOSE FIBROUSMATERIAL ABOVE THE RIDGES OF SAID CORRUGATED BASE LAYER, SAID BASEFABRIC HAVING UPTURNED EDGE PORTIONS FORMING SIDE WALLS EXTENDINGSUBSTANTIALLY THE THICKNESS OF THE BLANKET JOINED EDGEWISE TO SAID OUTERCOVERING LAYER AND FORMING AN ENVELOPE THEREWITH.